dissolve app/ into repo root (D-056)

Single Flutter package at the repo root. All code, tests, assets,
and platform directories moved from app/ to root. Package renamed
from clide_app to clide — all imports rewritten. Merged pubspec
combines core (ffi) and app (flutter, yaml, xterm) dependencies.
Makefile simplified: no APP_PRESENT conditionals, no cd, no daemon
lifecycle. 317 tests pass.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

lib/widgets/src/icons/warning.dart

@@ -0,0 +1,28 @@
+import 'dart:ui';
+import 'package:clide/widgets/src/clide_icon.dart';
+
+class WarningIcon extends ClideIconPainter {
+  const WarningIcon();
+
+  @override
+  void paint(Canvas canvas, Color color) {
+    final paint = Paint()
+      ..color = color
+      ..style = PaintingStyle.stroke
+      ..strokeWidth = 0.08
+      ..strokeCap = StrokeCap.round
+      ..strokeJoin = StrokeJoin.round;
+    final path = Path()
+      ..moveTo(0.5, 0.15)
+      ..lineTo(0.85, 0.8)
+      ..lineTo(0.15, 0.8)
+      ..close();
+    canvas.drawPath(path, paint);
+    // Exclamation
+    canvas.drawLine(const Offset(0.5, 0.4), const Offset(0.5, 0.58), paint);
+    final dot = Paint()
+      ..color = color
+      ..style = PaintingStyle.fill;
+    canvas.drawCircle(const Offset(0.5, 0.68), 0.035, dot);
+  }
+}